In many process flow systems, such as those employed for the treatment of drinking water, waste water, and dialysis equipment for the treatment of human blood, numerous on/off valves are required to direct the flow of fluid properly along a selected path. Although visual inspection of the positions of the handles of the valves enables an operator to determine whether the various valves are in the open or closed position, the operator must still verify that such are the correct positions necessary to direct the fluid along the selected path for a given application. At present, verification of the correct positioning of the valves is carried out by the operator verifying the open/closed position of each valve against a process flow diagram. Not only is this verification a tedious, time consuming process, but it lends itself to operator error such as the misreading of the flow diagram or improper identification of the valves. In some process flow systems, such as those mentioned above, a mispositioned valve can have serious, potentially life-threatening implications.,